Physisorption of trichloroethylene and tetrachloroethylene on novel zeta arsenene nanotubes - A first-principles study.

The structural stability of novel ζ-arsenene nanotubes (ζ-AsNT) is studied based on the density functional theory framework and is used as a base material for the detection of trichloroethylene and tetrachloroethylene vapours. The formation energy of ζ-AsNT is found to be -4.321 eV/atom and the energy band gap is 0.304 eV. Besides, the changes in the electronic properties of ζ-AsNT are explored with regard to the projected density of states, charge transfer, and electron density difference. The bandgap energy decreases for hollow site orientation to 0.205 and 0.204 eV for trichloroethylene and tetrachloroethylene vapours and increases for the valley and top site orientations. The adsorption energies were maximum for the valley site orientation of target molecules onto ζ-AsNT (01.165 and -1.513 eV for trichloroethylene and tetrachloroethylene, respectively). Moreover, the target vapours trichloroethylene and tetrachloroethylene are physisorbed on ζ-AsNT enabling the recycling of base substrate for continuous operation. The average energy gap changes vary from 18 to 32.9% depending on adsorption sites. The variation in the average energy gap owing to adsorption of trichloroethylene and tetrachloroethylene indicates the chemo-sensing nature of ζ-AsNT. The current report lays the inroads in the development of a new sensing element for the detection of chloroethylene molecules.